With the significant development of technologies related to lithium battery materials, secondary batteries have been made available as power sources that can meet high requirements on the electric quantity (for example, lithium iron phosphate oxide), and can be used in electric bicycles, electric wheelchairs, and other equipment having high requirements on the electric power. The battery cell of such a high-capacity lithium battery has larger electricity storage capacity and electricity supply capacity than those of traditional lithium batteries.
As shown in FIG. 1, an existing high-capacity prismatic lithium battery structure includes a plurality of soft package lithium batteries 10 (two soft package lithium batteries 10 are illustrated in the figure by way of example). The soft package lithium batteries 10 are each formed by a positive electrode layer, an isolation layer, and a negative electrode layer that are stacked together, and a positive-electrode conduction region 11 and a negative-electrode conduction region 12 are respectively provided on two sides of the soft package lithium battery 10. The soft package lithium batteries 10 are electrically connected to two extending portions 21 and 22 at two lower ends of a cover plate 20 by means of the positive-electrode conduction region 11 and the negative-electrode conduction region 12, and the extending portions 21 and 22 are respectively electrically connected to electrode ends 31 and 32 above the cover plate 20 by means of fasteners 22 (for example, rivets) that pass through the body of the cover plate 20, thereby obtaining an electrically conductive connection structure for discharging to the outside. In practice, insulation spacers 33 are provided below the electrode ends 31 and 32 above the cover plate 20, and an insulation block 40 and an insulation plate 41 are provided between the negative-electrode extending portion 22 and the electrode end 32 to avoid short circuits between the positive and negative electrodes.
Finally, the soft package lithium battery 10 is mounted at an opening of a housing 50 of a metal material, and the cover plate 20 and the periphery of the opening of the housing 50 are sealed by using different sealing techniques, for example, laser welding, thus obtaining an lithium battery cell structure of the secondary battery.
However, in the internal structure of an existing lithium battery cell structure, the extending portions 21 and 22 below the cover plate 20 are fixed below the cover plate 20, and the soft package lithium batteries 10 are respectively welded or connected to the extending portions 21 and 22 by means of the positive-electrode conduction region 11 and the negative-electrode conduction region 12 whose two sides are also perpendicular to the surface of the cover plate 20. Therefore, the extending portions 21 and 22 need to structurally correspond to the number of the soft package lithium battery 10; as two soft package lithium batteries 10 are illustrated in the figure by way of example, there are two extending portions 21 and 22 at two lower ends of the cover plate 20. Each cell 10 is sequentially welded or riveted to the extending portions 21 and 22 by means of the positive-electrode conduction region 11 and the negative-electrode conduction region 12. This welding or riveting process may lead to such problems as that the welding operation is time and labor consuming and that the positive-electrode conduction region 11 and the negative-electrode conduction region 12 cannot easily enter into electrical contact with the extending portions 21 and 22. In addition, to facilitate the installation of the soft package lithium battery 10 into the housing 50 during assembly, more space is needed inside the housing 50. The installation of the soft package lithium battery 10 into the housing 50 also often makes it not easy to implement the final sealing process.